HTC users, if you can’t login to your Twitter account via HTC Peep or FriendStream because of incorrect username and/or password, it’s not because your account has been hacked. Twitter suddenly switched to OAuth to authorize logins and HTC Peep doesn’t support that change yet.
HTC Peep and FriendStream (and other 3rd party Twitter apps) uses the old method called Basic Auth which stores username and password on third-party service. Twitter’s switch to OAuth doesn’t require other services to manage your logins anymore.
So what can you do? You can download the official Twitter mobile app for your phone or tweet from the browser instead while waiting for HTC to release an update on their Peep/FriendStream.
Of course, don’t discount the fact that your account may indeed be hacked if all else fails.